Self-sterilization using silicone catheters coated with Ag and TiO2 nanocomposite thin film

Ag/titanium dioxide (TiO2)-coated silicon catheters were easily fabricated with Ag nanoparticles deposition on both the inside wall and the outside wall of TiO2-coated catheters by TiO2 photocatalysis. This is an application of the silicon catheters coated with TiO2, which possess a self-sterilizing and self-cleaning property combining with UV light illumination (Ohko et al., J Biomed Mater Res: Appl Biomater 2001;58:97). Ag/TiO2-coated silicon catheters exhibited a strong bactericidal effect even in the dark. When the 2-5 X 10(5)w of colony-forming units of Escherichia coli, Pseudomonas aeruginosa, or Staphylococcus aureus were respectively applied to the surface of the Ag/TiO2 catheters, which were loaded with similar to 15 nmol cm(-2) of Ag, 99% effective sterilization occurred in a very short time: 20 min for E. coli, 60 min for P. aeruginosa, and 90 min for S. aureus. Additionally, the Ag/TiO2-coated catheters possessed a strong self-cleaning property. Using UV illumination, the photocatalytic decomposition rate of methylene blue dye representing the self-cleaning capability, on an Ag/TiO2 catheter which was loaded with 2 nmol cm-2 of Ag, was similar to 1.2 times higher (at maximum) than that on TiO2 coating alone. Furthermore, the Ag nanoparticles can be pre-eminently and uniformly deposited onto the TiO2 coating, and the amount of Ag was easily controllable from a few nanomoles per square centimeter to similar to 70 nmol cm(-2) by changing the UV illumination time for TiO2 photocatalysis. This type of catheter shows a great promise in lowering the incidence of catheter-related bacterial infections. (c) 2007 Wiley Periodicals, Inc.